Cardiac activity control of gastric electrical stimulator

Abstract

Methods and systems for stimulating a gastrointestinal system and for modifying a stimulation signal based on an indicator of autonomic nervous system function are described. One indicator of autonomic nervous system described is cardiac activity, including heart rate variability. Methods for selecting candidate patients for gastrointestinal stimulation therapy based on an indicator of autonomic nervous system function and methods of treating patients at risk of or suffering from gastrointestinal disorders by modifying therapy based on an indicator of autonomic function are also discussed.

1 . A method for identifying a candidate patient for digestive stimulation therapy, comprising:
 selecting a patient suffering from or at risk of a gastrointestinal disorder;   detecting cardiac activity of the patient; and   determining whether the detected cardiac activity is indicative of autonomic dysfunction,   wherein the patient is identified as a candidate for digestive stimulation therapy if the detected cardiac activity is indicative of autonomic dysfunction.   
     
     
         2 . The method of  claim 1 , wherein detecting cardiac activity comprises detecting heart rate variability. 
     
     
         3 . The method of  claim 2 , wherein detecting heart rate variability comprises analyzing a power spectrum of cardiac electrical activity. 
     
     
         4 . The method of  claim 3 , wherein analyzing a power spectrum of cardiac electrical activity comprises analyzing the spectrum in a low frequency range of between about 0.04 Hz to about 0.15 Hz. 
     
     
         5 . The method of  claim 4 , wherein analyzing a power spectrum of cardiac electrical activity further comprises analyzing the spectrum in a high frequency range of between about 0.18 Hz to about 0.4 Hz. 
     
     
         6 . The method of  claim 5 , wherein analyzing a power spectrum of cardiac electrical activity comprises comparing power of the low frequency range to power of the high frequency range. 
     
     
         7 . The method of  claim 3 , wherein analyzing a power spectrum of cardiac electrical activity comprises analyzing the spectrum in a high frequency range of between about 0.18 Hz to about 0.4 Hz. 
     
     
         8 . The method of  claim 2 , wherein detecting heart rate variability comprises determining a standard deviation of mean R-R intervals. 
     
     
         9 . The method of  claim 1 , further comprising:
 applying a stimulation signal directly to at least a portion of a digestive system; and   redetecting the cardiac activity after applying the stimulation signal;   wherein determining whether the detected cardiac activity is indicative of autonomic dysfunction comprises determining whether the redected cardiac activity is indicative of an improvement in autonomic nervous system function, and   wherein the patient is identified as a candidate for digestive stimulation therapy if the redetected cardiac activity is indicative of an improvement in autonomic nervous system function.   
     
     
         10 . The method of  claim 9 , wherein the stimulation signal is applied directly to the stomach. 
     
     
         11 . The method of  claim 9 , wherein the stimulation signal is applied directly to the stomach pacemaker region. 
     
     
         12 . The method of  claim 9 , wherein the stimulation is applied directly to a muscle wall of the stomach. 
     
     
         13 . The method of  claim 12 , wherein the stimulation is applied to an oblique layer, a circular layer or a longitudinal layer of the muscular wall of the stomach. 
     
     
         14 . The method of  claim 9 , wherein the stimulation is applied directly to one or more of a serosa layer, a myenteric plexus, and a submucosal plexus of the stomach. 
     
     
         15 . The method of  claim 9 , wherein the stimulation signal is applied directly to the duodenum. 
     
     
         16 . The method of  claim 9 , wherein the stimulation signal is applied directly to the intestine. 
     
     
         17 . The method of  claim 9 , wherein the stimulation signal is applied directly to the pancreas.